Methods for Fluid Monitoring in a Subterranean Formation Using One or More Integrated Computational Elements

ABSTRACT

Methods for fluid monitoring within a subterranean formation can comprise: introducing a first fluid into a subterranean formation; and monitoring a disposition of the first fluid within the subterranean formation using one or more integrated computational elements in optical communication with the subterranean formation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/198,915, filed Aug. 5, 2011, which is incorporated herein byreference in its entirety.

BACKGROUND

The present invention generally relates to methods for fluid monitoring,and, more specifically, to methods for monitoring the disposition of afluid in a subterranean formation.

When conducting operations within a subterranean formation, it canoftentimes be desirable to know with some precision the constituentconcentrations and/or characteristics of a fluid present in, beingintroduced to, or being produced from the formation. As used herein, theterm “constituent” will be used to refer to a substance present within afluid. As used herein, the term “characteristic” will be used to referto the value of a chemical property or a physical property, which alsomay include an optical property or a mechanical property. Classically,it has been conventional to sample fluids encountered in the course ofconducting subterranean operations and analyze them using off-linelaboratory analyses, including spectroscopic and/or wet chemicalmethods. Although such retrospective analyses can be satisfactory inmany instances, they are usually not sufficiently rapid to allowreal-time or near real-time process control to take place.

Once removed from a subterranean environment, many fluids may exhibitdifferent properties than they do downhole. Although fluids can besampled from a subterranean environment and brought to the surface foranalysis, there is generally no way to conclusively determine if thefluid has been changed in some manner during transit. In addition,highly specialized sampling techniques can often be needed, potentiallyadding to process complexity and costs. As an added difficulty, downholefluid analysis techniques can oftentimes be difficult to perform andinterpret. Many conventional spectroscopic instruments lack theruggedness needed for deployment in the harsh conditions of asubterranean environment. More rugged techniques suitable for beingcarried out downhole may not be sufficiently rapid to allow real-time ornear real-time process control to take place.

In addition to analyzing a fluid while it is downhole, it can oftentimesbe desirable to know the downhole disposition of a fluid following itsintroduction to a subterranean formation. For example, it can bedesirable to understand the zonal placement of a fluid in thesubterranean formation, but many methods for determining downhole fluiddisposition can be difficult to carry out and interpret. One techniquethat has been commonly used to determine fluid disposition withinsubterranean formations is distributed temperature sensing (DTS), whichmonitors the thermal front of an injected fluid in comparison to theformation temperature. Thief zones, cross-flow across producing zones,geothermal gradients, formation water, and other factors can complicatea DTS fluid disposition analysis. In addition, DTS analyses can takeseveral hours to acquire and interpret, again precluding real-time ornear real-time process control.

Placement of a fluid in an intended region of a subterranean formationcan be particularly problematic when there are multiple subterraneanzones within the formation, each zone likely having a differenteffective fluid permeability. One way in which the problem ofdifferential permeability can be addressed is though fluid diversionoperations, which may involve physical diversion (e.g., packers) orchemical diversion. Chemical diverting agents (e.g., relativepermeability modifiers, sealant compositions, and the like) may form afluid barrier within the subterranean formation that at least partiallyredirects the fluid flow to a different subterranean zone, often a zonewith a lower effective fluid permeability. Without employing fluiddiversion techniques, a fluid may naturally flow to the subterraneanzone having the highest effective fluid permeability. This can lead toover-stimulation of some subterranean zones while leaving othersubterranean zones under-stimulated. For example, in a wellbore having asubstantially horizontal section, the heel of the wellbore may beover-stimulated by a fluid being introduced thereto, while the toe ofthe wellbore receives insufficient fluid and is under-stimulated. Ineven more extreme cases, a fluid may enter a subterranean zone where itspresence can be unwanted and detrimental, resulting in reducedproduction and/or formation damage. Thus, improper fluid placement in asubterranean formation can have significant economic ramifications dueto waste of material goods, loss of production time, and time andexpense of potential remediation operations.

Although fluid diversion techniques can oftentimes be used successfullyin subterranean operations to direct a fluid to a desired subterraneanzone, the previously mentioned issues regarding determination of theultimate fluid disposition in the subterranean formation may stillremain. Namely, it may still be difficult to rapidly determine if afluid diversion operation has resulted in the intended redirection ofanother fluid. Likewise, there is no way to rapidly determine if adiverting fluid itself has been placed in the correct location within asubterranean formation to properly redirect another fluid to a differentlocation. In addition to proper placement of a diverting fluid, chemicalcompatibility of the diverting fluid with the subterranean formation ora fluid therein can impact the ultimate success of a fluid diversionoperation.

Injection operations are another subterranean operation in which it canbe highly desirable to know the subterranean disposition of a fluid. Ininjection operations, an injection fluid, often containing a dye or liketracer, is introduced into a wellbore that is fluidly connected to oneor more neighboring wellbores. The fluid pressure in the injectionwellbore may be used to drive the production of another fluid from theneighboring wellbore(s). Besides merely observing increased productionfrom the neighboring wellbore(s), the success of an injection operationcan also be evaluated by analyzing the neighboring wellbore(s) for theinjection fluid (e.g., by analyzing for migration of the tracer from theinjection wellbore to the neighboring wellbore(s)).

In addition to evaluating the disposition of a fluid within asubterranean formation, it can also be desirable to know if the fluid isproducing a desired effect therein. Evidence of a fluid producing adesired effect may include, for example, the creation or lack ofcreation of a substance in the presence or absence of the fluid. By wayof non-limiting example, in an acidizing operation, the formation matrixmay react with an acid to produce soluble species that may not otherwisebe present in abundance. It should be noted that even if a fluid isdisposed as intended in a subterranean formation, the intended effect ofintroducing the fluid is not necessarily guaranteed to be achieved. Forexample, the flow rate of the fluid past the formation matrix may be toofast or too slow for the fluid to have its intended effect, or the fluiditself may sometimes be insufficient in some manner. In even moreextreme instances, a fluid may interact with a component of theformation matrix in an unwanted manner to produce damage in thesubterranean formation.

Carbonate formations are one type of subterranean formation in which itcan be highly desirable to know the disposition and effect of a fluidpresent therein, particularly an acidizing fluid. When acidizing acarbonate formation, it may be desirable to create wormholes in atreated subterranean zone in order to increase the formation'spermeability. In some instances, even if an acidizing fluid is directedto an intended zone of a carbonate formation, wormhole creation may notoccur. For example, if the acidizing fluid is not introduced to theformation at the proper rate, simple erosion of the surface of thesubterranean formation may occur, rather than the desired wormholecreation needed for effective stimulation to take place. Monitoring onlythe fluid disposition in this case may be insufficient to determine thesuccess or failure of the acidizing operation.

SUMMARY

The present invention generally relates to methods for fluid monitoring,and, more specifically, to methods for monitoring the disposition of afluid in a subterranean formation.

In some embodiments, the present disclosure provides methods comprising:introducing a first fluid into a subterranean formation; and monitoringa disposition of the first fluid within the subterranean formation usingone or more integrated computational elements in optical communicationwith the subterranean formation.

In some embodiments, the present disclosure provides methods comprising:providing an injection wellbore penetrating a subterranean formation,the injection wellbore being in fluid communication with one or moreneighboring wellbores; introducing an injection fluid to the injectionwellbore; and monitoring a progression of the injection fluid within theinjection wellbore or in the one or more neighboring wellbores using oneor more integrated computational elements in optical communication withthe injection wellbore or the one or more neighboring wellbores.

In some embodiments, the present disclosure provides methods comprising:providing a diverting fluid comprising a diverting agent; introducingthe diverting fluid into a subterranean formation comprising one or moresubterranean zones; after or while introducing the diverting fluid,introducing a treatment fluid to the subterranean formation; andmonitoring a disposition of the treatment fluid within the subterraneanformation using one or more integrated computational elements in opticalcommunication with the subterranean formation.

The features and advantages of the present invention will be readilyapparent to one having ordinary skill in the art upon a reading of thedescription of the preferred embodiments that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of thepresent invention, and should not be viewed as exclusive embodiments.The subject matter disclosed is capable of considerable modification,alteration, and equivalents in form and function, as will occur to onehaving ordinary skill in the art and the benefit of this disclosure.

FIG. 1 shows a schematic of a subterranean formation presenting anillustrative placement of integrated computational elements therein.

FIG. 2 shows a schematic of an illustrative integrated computationalelement.

DETAILED DESCRIPTION

The present invention generally relates to methods for fluid monitoring,and, more specifically, to methods for monitoring the disposition of afluid in a subterranean formation.

Despite the difficulties that can be encountered in monitoring one ormore fluids within a subterranean formation, significant benefits can berealized in doing so, particularly according to the methods describedherein. In contrast to conventional spectroscopic instruments andtechniques, the methods described herein utilize optical computingdevices containing an integrated computational element (ICE), which canbe well suited for deployment in a subterranean formation and analysisof a fluid's disposition therein. Each integrated computational elementwithin an optical computing device can be specifically configured todetect a constituent or characteristic of interest in a sample, evenwhen complex mixtures of constituents are present. The theory behindoptical computing and a description of some conventional opticalcomputing devices are provided in more detail in the following commonlyowned United States Patents and United States Patent ApplicationPublications, each of which is incorporated herein by reference in itsentirety: U.S. Pat. No. 6,198,531, U.S. Pat. No. 6,529,276, U.S. Pat.No. 7,123,844, U.S. Pat. No. 7,834,999, U.S. Pat. No. 7,911,605, U.S.Pat. No. 7,920,258, 20090219538, 20090219539, and 20090073433.Accordingly, the theory behind optical computing will not be discussedin any extensive detail herein unless needed to better describe one ormore embodiments of the present disclosure. Unlike conventionalspectroscopic instruments, which produce a spectrum needing furtherinterpretation to obtain a result, the ultimate output of opticalcomputing devices is a real number that can be correlated in some mannerwith a constituent concentration or characteristic of a sample. Theoperational simplicity of optical computing devices allows them torapidly output a result, in real-time or near real-time, in someembodiments.

In addition, significant benefits can be realized by combining theoutputs of two or more integrated computational elements with oneanother when analyzing a single constituent or characteristic ofinterest. Specifically, in some instances, significantly increaseddetection accuracy may be realized. Detection techniques forconstituents and characteristics using combinations of two or moreintegrated computational elements are described in commonly owned U.S.patent application Ser. Nos. 13/456,255, 13/456,264, 13/456,283,13/456,302, 13/456,327, 13/456,350, 13/456,379, 13/456,405, and13/456,443, each filed on Apr. 26, 2012 and incorporated herein byreference in its entirety. It is to be recognized that any of theembodiments described herein may be carried out through combining theoutputs of two or more integrated computational elements with oneanother.

As alluded to above, the operational simplicity of optical computingdevices makes them rugged and well suited for field or processenvironments, including deployment within a subterranean formation. Usesof conventional optical computing devices for the analysis of fluids andother substances commonly encountered in the oil and gas industry,including while deployed within a subterranean formation, are describedin commonly owned U.S. patent application Ser. Nos. 13/198,915,13/198,950, 13/198,972, 13/204,005, 13/204,046, 13/204,123, 13/204,165,13/204,213, and 13/204,294, each filed on Aug. 5, 2011 and incorporatedherein by reference in its entirety. Illustrative materials that may beanalyzed by such techniques include, for example, treatment fluids(e.g., drilling fluids, acidizing fluids, fracturing fluids, and thelike), pipeline fluids, bacteria, carrier fluids, source materials,produced water, produced hydrocarbon fluids, subterranean surfaces, andthe like.

The present inventors recognized that the subsurface utility of opticalcomputing devices may be extended through using them to monitor fluiddisposition within a subterranean formation. The present inventors donot currently believe that there has been any contemplation in the artto use optical computing devices in this fashion. Use of opticalcomputing devices for monitoring fluid disposition within a subterraneanformation may present a number of advantages, as discussed hereinafter.

The present inventors contemplate deploying one or more integratedcomputational elements in optical communication with a subterraneanformation to monitor the location and movement of a fluid therein. Asused herein, the term “optical communication” refers to the receipt ofelectromagnetic radiation from within a subterranean formation. In someembodiments, the integrated computational element(s) may be locatedwithin the subterranean formation so as to receive electromagneticradiation therefrom. In other embodiments, the integrated computationalelement(s) may be located external to the subterranean formation but inoptical communication therewith by way of an optical fiber or likeelectromagnetic radiation conduit extending into the subterraneanformation. In either case, the integrated computational element(s) mayreceive electromagnetic radiation from one or more points of interestwithin the subterranean formation in order to evaluate the fluiddisposition therein.

Depending on the location(s) of the integrated computational element(s)in the subterranean formation, various types of information can bedetermined in real-time or near real-time based upon fluid flow into orout of the subterranean formation. For example, in some embodiments, theconsumption of a substance in a treatment fluid can be monitored as thetreatment fluid passes through various subterranean zones. In otherembodiments, the flow pathway(s) of the treatment fluid in thesubterranean formation can be monitored as the treatment fluid passesthe various integrated computational element(s). Information obtainedfrom the integrated computational element(s) can not only be used to mapthe morphology of the subterranean formation, but it can also indicatewhether a parameter of the treatment fluid needs to be changed in orderto perform a more effective treatment. For example, in some embodiments,the treatment fluid may be altered in order to address specificconditions that are being encountered downhole. In addition, in someembodiments, a treatment fluid can be monitored to ensure that it doesnot change in an undesirable way when introduced into the downholeenvironment. In the event that the treatment fluid undesirably changesupon being introduced downhole, the treatment fluid being introducedinto the subterranean formation can be modified or an additionalcomponent or an additional treatment fluid can be added separately tothe subterranean formation in order to address the undesired conditionpresent in the treatment fluid. In some embodiments, a treatment fluidcan be monitored downhole using integrated computational element(s) inorder to evaluate fluid displacement and fluid diversion in thesubterranean formation (e.g, the flow pathway). In such embodiments,real-time or near-real time data from the integrated computationalelement(s) can be used to adjust the placement of the fluid usingdiverting agents and to evaluate the effectiveness of diverting agents.Further, in some embodiments, after monitoring a disposition of thetreatment fluid using the integrated computational element(s), thetreatment fluid may be altered, if desired, to change the way in whichthe subterranean formation is being treated. In some embodiments, thediverting agents can be added to the treatment fluid in response to aresult obtained from the integrated computational element(s).

When utilized for analyzing a fluid within a subterranean formation, theintegrated computational element(s) may be present in a fixed locationor they may be movable. In some embodiments, the integratedcomputational element(s) may be affixed at one or more locations withinthe subterranean formation (e.g., on tubulars). In other embodiments,the integrated computational element(s) may be removably placed at oneor more locations within the subterranean formation, such as throughwireline deployment, for example. In some embodiments, at least oneintegrated computational element may be placed substantially adjacent toeach subterranean zone. Monitoring an output of the integratedcomputational element(s) at each subterranean zone may allow a zonalplacement of a fluid to be determined.

FIG. 1 shows a schematic of a subterranean formation presenting anillustrative placement of integrated computational elements therein. Asillustrated in FIG. 1, subterranean formation 1, which is penetrated bywellbore 10, contains subterranean zones 14, 16, and 18 therein. Asdepicted in FIG. 1, integrated computational elements 20 may be sitedsubstantially adjacent to each subterranean zone. Optionally oralternatively, in some embodiments, integrated computational element 22may be sited at the bottom of wellbore 10. For example, in someembodiments, integrated computational element 22 may be used to verifythat a treatment fluid has traversed the entire length of wellbore 10.As depicted in FIG. 1, integrated computational elements 20 and 22 aresited in subterranean formation 1 in a wireline-type deployment.However, as discussed above, it is to be understood that theconfiguration depicted in FIG. 1 is simply for purposes of illustrationand not limitation. Furthermore, the number of integrated computationalelements depicted in FIG. 1 and their deployment configuration is meantto be illustrative and non-limiting.

As discussed above, the operational simplicity of integratedcomputational elements may allow them to rapidly produce an output.Accordingly, monitoring fluid disposition within a subterraneanformation using one or more integrated computational elements may alsotake place at a comparable rate (e.g., in real-time or near real-time).This feature represents a key advantage of the present methods overother techniques for monitoring fluid disposition within a subterraneanformation, which frequently require much longer periods of time for dataanalysis. Accordingly, the present methods for monitoring fluiddisposition may allow more active process control to be realized withless downtime. For example, if it is identified that a diversionoperation has not resulted in satisfactory fluid diversion within asubterranean formation, the diversion operation can be repeated ormodified to result in a more satisfactory outcome. Although integratedcomputational elements may be used to monitor fluid disposition inreal-time or near real-time, it is to be recognized that the analyticaldata collected therewith may be stored and processed in an offlinemanner, if desired, in some embodiments.

As also discussed above, a significant benefit associated withintegrated computational elements is their ability to specificallyanalyze for a constituent or characteristic of interest. By deployingtwo or more integrated computational elements together at a location,each integrated computational element being configured for the analysisof a different constituent or characteristic of interest, one cansimultaneously monitor two or more different fluid attributes. In thecase of fluid diversion operations, for example, a first integratedcomputational element may be used to verify satisfactory placement of adiverting fluid, and a second integrated computational element may beused to verify that a subsequently introduced fluid is not entering aregion of the subterranean formation treated by the diverting fluid.That is, if the diverting operation has occurred as intended, thesubsequently introduced fluid should not substantially enter an areatreated by the diverting fluid and not be detected by the secondintegrated computational element. In some embodiments, a thirdintegrated computational element in another location may be used toverify that the subsequently introduced fluid has been directed to adesired region of the subterranean formation.

Another advantage of using integrated computational elements to monitorfluid disposition within a subterranean formation is that they may beused to analyze what happens within the subterranean formation once thefluid reaches its intended location. For example, it may be desirable toverify that the fluid maintains a desired constituent concentration orcharacteristic of interest once delivered to a given location, orwhether a reaction product is being created or not in the presence ofthe fluid. Thus, in some embodiments, integrated computational elementsmay be used dually for analyzing fluid disposition and assessing whathappens within the subterranean formation in the presence of the fluid.In some embodiments, the same integrated computational element(s) may beused for such dual analysis of the fluid. In other embodiments,different integrated computational elements may be used for thispurpose. For example, in some embodiments, a first integratedcomputational element may be used to assess fluid disposition and asecond integrated computational element may be used to determine whathappens in the presence of the fluid. In some embodiments, the fluid maybe altered in response to the condition measured by the secondintegrated computational element.

In some embodiments, it may be desirable to utilize a plurality ofintegrated computational elements to monitor a fluid as it progressesthrough a subterranean formation. The same or different integratedcomputational elements may be used to obtain a spatial profile of thefluid's constituent concentration(s) or characteristic(s) of interestwithin the subterranean formation. For example, it may be desirable todetermine how a fluid is changing as it progresses to its end locationwithin the subterranean formation. Changes observed in the fluid as itprogresses to its end location may be used to determine whether atreatment fluid needs to be introduced to the subterranean formation orif the fluid needs to be otherwise altered in some manner, for example.

As used herein, the term “fluid” refers to any substance that is capableof flowing, including particulate solids, liquids, gases, slurries,emulsions, powders, muds, glasses, any combination thereof, and thelike. In some embodiments, the fluid can be an aqueous fluid, includingwater, mixtures of water and water-miscible fluids, and the like. Insome embodiments, the fluid can be a non-aqueous fluid, includingorganic compounds (i.e., hydrocarbons, oil, a refined component of oil,petrochemical products, and the like). In some embodiments, the fluidcan be a treatment fluid or a formation fluid.

As used herein, the term “treatment fluid” refers to a fluid that isplaced in a subterranean formation or in a pipeline in order to performa desired function. Treatment fluids can be used in a variety ofsubterranean operations, including, but not limited to, drillingoperations, production treatments, stimulation treatments, remedialtreatments, fluid diversion operations, fracturing operations, secondaryor tertiary enhanced oil recovery (EOR) operations, and the like. Asused herein, the terms “treat,” “treatment,” “treating,” and othergrammatical equivalents thereof refer to any operation that uses a fluidin conjunction with performing a desired function and/or achieving adesired purpose. The terms “treat,” “treatment,” and “treating,” as usedherein, do not imply any particular action by the fluid or anyparticular component thereof unless otherwise specified. Treatmentfluids for subterranean operations can include, for example, drillingfluids, fracturing fluids, acidizing fluids, conformance treatmentfluids, damage control fluids, remediation fluids, scale removal andinhibition fluids, chemical floods, and the like.

As used herein, the terms “real-time” and “near real-time” refer to anoutput by an integrated computational element that is produced onsubstantially the same time scale as the optical interrogation of asubstance with electromagnetic radiation. That is, a “real-time” or“near real-time” output does not take place offline after dataacquisition and post-processing techniques. An output that is returnedin “real-time” may be returned essentially instantaneously. A “nearreal-time” output may be returned after a brief delay, which may beassociated with processing or data transmission time, or the like. Itwill be appreciated by one having ordinary skill in the art that therate at which an output is received may be dependent upon the processingand data transmission rate. In some embodiments described herein, thedisposition of a fluid within a subterranean formation may be determinedin real-time or near real-time using one or more integratedcomputational elements in optical communication with the subterraneanformation.

As used herein, the term “disposition” refers to a substance's spatiallocation without reference to a point of time.

As used herein, the term “position” and grammatical equivalents thereofrefer to a substance's spatial location at a fixed point in time.

As used herein, the term “progression” and grammatical equivalentsthereof refer to a substance's movement between a series of locationsover a period of time.

As used herein, the term “placement” and grammatical equivalents thereofrefer to a substance's end position following its progression.

As used herein, the term “electromagnetic radiation” refers to radiowaves, microwave radiation, infrared and near-infrared radiation,visible light, ultraviolet radiation, X-ray radiation, and gamma rayradiation.

FIG. 2 shows a schematic of an illustrative integrated computationalelement (ICE) 100. As illustrated in FIG. 2, ICE 100 may include aplurality of alternating layers 102 and 104 of varying thicknessesdisposed on optical substrate 106. In general, the materials forminglayers 102 and 104 have indices of refraction that differ (i.e., one hasa low index of refraction and the other has a high index of refraction),such as Si and SiO₂. Other suitable materials for layers 102 and 104 mayinclude, but are not limited to, niobia and niobium, germanium andgermania, MgF, and SiO. Additional pairs of materials having high andlow indices of refraction can be envisioned by one having ordinary skillin the art, and the composition of layers 102 and 104 is not consideredto be particularly limited. In some embodiments, the material withinlayers 102 and 104 can be doped, or two or more materials can becombined in a manner to achieve a desired optical response. In additionto solids, ICE 100 may also contain liquids (e.g., water) and/or gases,optionally in combination with solids, in order to produce a desiredoptical response. The material forming optical substrate 106 is notconsidered to be particularly limited and may comprise, for example,BK-7 optical glass, quartz, sapphire, silicon, germanium, zinc selenide,zinc sulfide, various polymers (e.g., polycarbonates,polymethylmethacrylate, polyvinylchloride, and the like), diamond,ceramics, and the like. Opposite to optical substrate 106, ICE 100 mayinclude layer 108 that is generally exposed to the environment of thedevice or installation in which it is used.

The number, thickness, and spacing of layers 102 and 104 may bedetermined using a variety of approximation methods based upon aconventional spectroscopic measurement of a sample. These methods mayinclude, for example, inverse Fourier transform (IFT) of the opticaltransmission spectrum and structuring ICE 100 as a physicalrepresentation of the IFT. The approximation methods convert the IFTinto a structure based on known materials with constant refractiveindices.

It should be understood that illustrative ICE 100 of FIG. 2 has beenpresented for purposes of illustration only. Thus, it is not impliedthat ICE 100 is predictive for any particular constituent orcharacteristic of a given fluid. Furthermore, it is to be understoodthat layers 102 and 104 are not necessarily drawn to scale and shouldtherefore not be considered as limiting of the present disclosure.Moreover, one having ordinary skill in the art will readily recognizethat the materials comprising layers 102 and 104 may vary depending onfactors such as, for example, the types of substances being analyzed andthe ability to accurately conduct their analysis, cost of goods, and/orchemical compatibility issues.

It is to be recognized the embodiments herein may be practiced withvarious blocks, modules, elements, components, methods and algorithms,which can be implemented through using computer hardware, software andcombinations thereof. To illustrate this interchangeability of hardwareand software, various illustrative blocks, modules, elements,components, methods and algorithms have been described generally interms of their functionality. Whether such functionality is implementedas hardware or software will depend upon the particular application andany imposed design constraints. For at least this reason, it is to berecognized that one of ordinary skill in the art can implement thedescribed functionality in a variety of ways for a particularapplication. Further, various components and blocks can be arranged in adifferent order or partitioned differently, for example, withoutdeparting from the spirit and scope of the embodiments expresslydescribed.

Computer hardware used to implement the various illustrative blocks,modules, elements, components, methods and algorithms described hereincan include a processor configured to execute one or more sequences ofinstructions, programming or code stored on a readable medium. Theprocessor can be, for example, a general purpose microprocessor, amicrocontroller, a digital signal processor, an application specificintegrated circuit, a field programmable gate array, a programmablelogic device, a controller, a state machine, a gated logic, discretehardware components, an artificial neural network or any like suitableentity that can perform calculations or other manipulations of data. Insome embodiments, computer hardware can further include elements suchas, for example, a memory (e.g., random access memory (RAM), flashmemory, read only memory (ROM), programmable read only memory (PROM),erasable PROM), registers, hard disks, removable disks, CD-ROMS, DVDs,or any other like suitable storage device.

Executable sequences described herein can be implemented with one ormore sequences of code contained in a memory. In some embodiments, suchcode can be read into the memory from another machine-readable medium.Execution of the sequences of instructions contained in the memory cancause a processor to perform the process steps described herein. One ormore processors in a multi-processing arrangement can also be employedto execute instruction sequences in the memory. In addition, hard-wiredcircuitry can be used in place of or in combination with softwareinstructions to implement various embodiments described herein. Thus,the present embodiments are not limited to any specific combination ofhardware and software.

As used herein, a machine-readable medium will refer to any medium thatdirectly or indirectly provides instructions to a processor forexecution. A machine-readable medium can take on many forms including,for example, non-volatile media, volatile media, and transmission media.Non-volatile media can include, for example, optical and magnetic disks.Volatile media can include, for example, dynamic memory. Transmissionmedia can include, for example, coaxial cables, wire, fiber optics, andwires that form a bus. Common forms of machine-readable media caninclude, for example, floppy disks, flexible disks, hard disks, magnetictapes, other like magnetic media, CD-ROMs, DVDs, other like opticalmedia, punch cards, paper tapes and like physical media with patternedholes, RAM, ROM, PROM, EPROM and flash EPROM.

In some embodiments, methods described herein may comprise: introducinga first fluid into a subterranean formation; and monitoring adisposition of the first fluid within the subterranean formation usingone or more integrated computational elements in optical communicationwith the subterranean formation.

In some embodiments, the methods may further comprise altering the firstfluid after monitoring its disposition within the subterraneanformation. For example, in some embodiments, once a disposition of thefirst fluid in the subterranean formation is known, a characteristic ofthe fluid may be altered to change its disposition in the subterraneanformation. Altering a characteristic of the fluid may comprise, forexample, changing the fluid's viscosity, pH, specific gravity, or thelike. In some embodiments, the fluid's chemical composition may bealtered by adding another constituent to the fluid.

In some embodiments, monitoring a disposition of a fluid using one ormore integrated computational elements may take place in real-time ornear real-time. In other various embodiments, data acquired using theintegrated computational element(s) may be stored and processed offlineat a later time. Furthermore, in still other embodiments, remotemonitoring of the integrated computational element(s) may take place.

In some embodiments, one or more of the integrated computationalelements may be present in the subterranean formation. In some or otherembodiments, one or more of the integrated computational elements may beoptically connected to the subterranean formation via an optical fiberor like conduit for electromagnetic radiation extending into thesubterranean formation. In some embodiments, the subterranean formationmay be penetrated by a wellbore, where the one or more integratedcomputational elements are located within the wellbore.

In some embodiments, fluid disposition within a subterranean formationmay be monitored using one integrated computational element that is inoptical communication with the subterranean formation. For example, insome embodiments, the integrated computational element may be used toassess if a fluid has reached or passed a location in the subterraneanformation at which the integrated computational element is sited or withwhich the integrated computational element is in optical communication.In other embodiments, there may be a plurality of integratedcomputational elements in optical communication with the subterraneanformation. In some embodiments, there may be a plurality of integratedcomputational elements sited at multiple locations within a wellbore orin optical communication with multiple locations within a wellbore.Monitoring fluid disposition using a plurality of integratedcomputational elements may take place similarly to that described forone integrated computational element. However, when a plurality ofintegrated computational elements is present, dynamics of the fluid flowwithin a subterranean formation may be more readily determined.

When a plurality of integrated computational elements are used formonitoring fluid disposition, any number of integrated computationalelements may be present. In some embodiments, there may be 2 integratedcomputational elements, or 3 integrated computational elements, or 4integrated computational elements, or 5 integrated computationalelements, or 6 integrated computational elements, or 7 integratedcomputational elements, or 8 integrated computational elements, or 9integrated computational elements, or 10 integrated computationalelements. In some embodiments, there may be about 10 or more integratedcomputational elements, or about 20 or more integrated computationalelements, or about 50 or more integrated computational elements, orabout 100 or more integrated computational elements, or about 200 ormore integrated computational elements, or about 300 or more integratedcomputational elements, or about 400 or more integrated computationalelements, or about 500 or more integrated computational elements, orabout 1000 or more integrated computational elements. Given the benefitof the present disclosure and the particular fluid dispositioninformation desired to be obtained, one of ordinary skill in the artwill be able to choose a sufficient number of integrated computationalelements and their siting in a subterranean formation to accomplish agiven task.

In some embodiments, an integrated computational element may be sited ator in optical communication with about every 10 feet within thesubterranean formation. In other embodiments, an integratedcomputational element may be sited at or in optical communication withabout every 20 feet within the subterranean formation, or about every 30feet, or about every 40 feet, or about every 50 feet, or about every 100feet, or about every 200 feet, or about every 300 feet, or about every400 feet, or about every 500 feet. Spacing of the integratedcomputational elements within the subterranean formation may be regularor irregular depending on the particular attributes of the formationthat will be evident to one having ordinary skill in the art. Further,in some embodiments, more than one integrated computational element maybe present at some sites, while other sites have only one integratedcomputational element. In other embodiments, each site may have morethan one integrated computational element. In still other embodiments,each site may have one integrated computational element.

In some embodiments, the subterranean formation may comprise one or moresubterranean zones, and at least one integrated computational elementmay be sited substantially adjacent to each subterranean zone or inoptical communication with a location substantially adjacent to eachsubterranean zone. As used herein, the term “subterranean zone” refersto a region of a subterranean formation that has a permeability orcomposition differing from an adjacent region of the subterraneanformation. Use of a plurality of integrated computational elements inthis manner may allow one to determine whether a fluid has beendelivered to a desired or undesired subterranean zone.

In some embodiments, monitoring a disposition of a fluid within asubterranean formation may comprise monitoring for a constituent withinthe fluid or monitoring a characteristic of a fluid. Monitoring aconstituent within the fluid may comprise monitoring its concentration,for example. In various embodiments, monitoring a disposition of a fluidwithin a subterranean formation may comprise determining a placement ofthe fluid within the subterranean formation. For example, in someembodiments, monitoring a disposition of the fluid in a subterraneanformation may comprise monitoring a placement of the fluid within asubterranean zone. In other various embodiments, monitoring adisposition of a fluid within a subterranean formation may comprisedetermining a progression of the fluid within the subterraneanformation. For example, in some embodiments, a plurality of integratedcomputational elements may be used to determine the progression of afluid within a wellbore penetrating a subterranean formation.

As discussed above, constituents present within a fluid orcharacteristics of a fluid may be monitored using one or more integratedcomputational elements according to the embodiments described herein. Ingeneral, any constituent present within a fluid can be monitored usingan integrated computational element configured to analyze for theconstituent. Characteristics of a fluid may be monitored using anintegrated computational element in a like manner. Characteristics of afluid that can be monitored using an integrated computational elementmay include both chemical properties and physical properties, which mayalso include optical properties and mechanical properties. Illustrativecharacteristics of a fluid that may be monitored using an integratedcomputational element may include, without limitation, viscosity, ionicstrength, pH, total dissolved solids, total dissolved salt, density,total particulate solids, opacity, bacteria content, and the like.

In some embodiments, monitoring a disposition of a fluid within thesubterranean formation may comprise detecting a constituent or acharacteristic of the fluid, a reaction product formed from aconstituent of the fluid, a substance formed in the presence of thefluid, a substance formed in the absence of the fluid, a decline in asubstance formed in the absence of a fluid, or any combination thereof.Monitoring any of these parameters may allow one to determine where thefluid has travelled or is present within the subterranean formation.

In some embodiments, it may be desirable to both monitor the dispositionof a fluid in the subterranean formation and to analyze for aconstituent or characteristic of the fluid. For example, after a fluidhas reached its end location in the subterranean formation, it may thenbe desirable to know if the fluid composition and characteristics arestill within acceptable parameters. In some embodiments, after or whilemonitoring a disposition of the fluid within the subterranean formation,the methods may further comprise analyzing for a constituent or acharacteristic of the fluid using one or more integrated computationalelements. In some embodiments, the constituent or characteristic beinganalyzed may be the same as those used to determine the disposition ofthe fluid. In other embodiments, the constituent or characteristic beinganalyzed may be different. In embodiments in which differentconstituents or characteristics are being analyzed, more than oneintegrated computational element may be sited at or in opticalcommunication with the same location, where the integrated computationalelements are differentially configured to analyze for differentconstituents or characteristics. That is, in such embodiments, a firstintegrated computational element may be used for monitoring fluiddisposition and a second integrated computational element may be used tomonitor a constituent or characteristic of the fluid during or after itsplacement in the subterranean formation.

In some embodiments, the fluid being monitored by the one or moreintegrated computational elements may comprise a treatment fluid.Treatment fluids that may be monitored according to the embodimentsdescribed herein include, for example, drilling fluids, fracturingfluids, gravel packing fluids, acidizing fluids, conformance controlfluids, gelled fluids, fluids comprising a relative permeabilitymodifier, diverting fluids, fluids comprising a breaker, biocidaltreatment fluids, remediation fluids, scale inhibitor fluids, corrosioninhibitor fluids, friction reducing fluids, any combination thereof, andthe like. In some embodiments, an injection fluid, such as used inenhanced oil recovery operations may be monitored.

In some embodiments, the treatment fluids described herein may comprisean aqueous carrier fluid. Suitable aqueous carrier fluids may include,but are not limited to, fresh water, acidified water, salt water,seawater, brine, aqueous salt solutions, surface water (i.e., streams,rivers, ponds and lakes), underground water from an aquifer, municipalwater, municipal waste water, or produced water from a subterraneanformation. In some or other embodiments, the treatment fluids maycomprise an oleaginous carrier fluid. Suitable oleaginous carrier fluidsmay include, for example, oil, hydrocarbons, water-in-oil emulsions, andthe like.

In some embodiments, after or while introducing a first fluid into thesubterranean formation and monitoring its disposition, a second fluidmay be introduced into the subterranean formation. For example, in someembodiments, after or while introducing a first fluid and determining ifthe first fluid has entered a desired region of the subterraneanformation, a second fluid may be introduced to the subterraneanformation. In some embodiments, the first fluid and the second fluid maybe the same, and in other embodiments, the first fluid and the secondfluid may be different. For example, in some embodiments, the firstfluid may comprise a diverting fluid and the second fluid may comprise adifferent treatment fluid, such as an acidizing fluid. Once a desiredplacement of the diverting fluid has been confirmed using the integratedcomputational element(s), the likelihood of directing the second fluidto a desired region of the subterranean formation may be increased. Insome embodiments, the methods may further comprise monitoring adisposition of the second fluid in the subterranean formation using oneor more integrated computational elements.

In the alternative, before introducing the first fluid to thesubterranean formation, the methods may further comprise performing adiverting operation in the subterranean formation. For example, in someembodiments, a diverting fluid may be introduced to the subterraneanformation prior to introducing the first fluid so as to direct the firstfluid to a desired location within the subterranean formation. In someembodiments, the disposition of the diverting fluid in the subterraneanformation may also be monitored using one or more integratedcomputational elements.

In some embodiments, methods described herein may comprise: providing adiverting fluid comprising a diverting agent; introducing the divertingfluid into a subterranean formation comprising one or more subterraneanzones; after or while introducing the diverting fluid, introducing atreatment fluid to the subterranean formation; and monitoring adisposition of the treatment fluid within the subterranean formationusing one or more integrated computational elements in opticalcommunication with the subterranean formation.

In some embodiments, monitoring a disposition of the treatment fluid inthe subterranean formation may comprise determining a placement of thetreatment fluid in the subterranean formation. In some embodiments,monitoring a disposition of the treatment fluid within the subterraneanformation may take place in real-time or near real-time.

In some embodiments, methods described herein may comprise: providing adiverting fluid comprising a diverting agent; introducing the divertingfluid into a subterranean formation comprising one or more subterraneanzones; and monitoring a disposition of the diverting fluid within thesubterranean formation using one or more integrated computationalelements in optical communication with the subterranean formation.

In some embodiments, monitoring a disposition of the diverting fluid inthe subterranean formation may comprise monitoring a placement of thediverting fluid in the subterranean formation, for example, in or nearone or more subterranean zones. In some embodiments, monitoring adisposition of the diverting fluid may comprise detecting the divertingagent or a reaction product formed therefrom, a characteristic of thediverting fluid, or any combination thereof.

In some embodiments, monitoring a disposition of the diverting fluidusing one or more integrated computational elements may take place inreal-time or near real-time. In other various embodiments, data acquiredusing the integrated computational element(s) may be stored andprocessed offline at a later time.

In some embodiments, the diverting fluid may comprise a non-reactivediverting agent. A non-reactive diverting agent may form an at leastpartially impermeable fluid barrier in a subterranean formation withoutundergoing a chemical reaction. Examples of non-reactive divertingagents may include, for example, relative permeability modifiers andparticulates that agglomerate to form a fluid barrier within thesubterranean formation. In other embodiments, the diverting fluid maycomprise a reactive diverting agent. A reactive diverting agent may forman at least partially impermeable fluid barrier in a subterraneanformation by forming a reaction product. Examples of reactive divertingagents may include, for example, adhesives, gellable polymers, and thelike that form a fluid barrier after undergoing a chemical reaction.

In some embodiments, after or while introducing the diverting fluid intoa subterranean formation and monitoring its disposition therein, asecond fluid may be introduced to the subterranean formation. In someembodiments, the second fluid may comprise a treatment fluid, which maycomprise any of those described above. If the diverting fluid hasfunctioned as intended, the treatment fluid will be directed away fromregions of the subterranean formation in which the diverting fluid hasformed a fluid seal or like barrier. In some embodiments, methodsdescribed herein may comprise introducing a treatment fluid to asubterranean formation after or while introducing a diverting fluid, andinteracting the treatment fluid with a subterranean zone. In someembodiments, the methods may further comprise monitoring disposition ofthe treatment fluid after its introduction to the subterraneanformation, using one or more integrated computational elements. Forexample, in some embodiments, the methods may further comprisemonitoring a placement of the treatment fluid in the subterraneanformation using one or more integrated computational elements that arein optical communication with the subterranean formation.

In more particular embodiments, the treatment fluid being introduced tothe subterranean formation after introduction of the diverting fluid maycomprise an acidizing fluid. As described above, proper placement of anacidizing fluid in a subterranean formation may be desirable, forexample, to avoid over stimulation of high permeability subterraneanzones in preference to lower permeability subterranean zones.

In some embodiments, methods described herein may comprise: providing anacidizing fluid comprising at least one acid or acid-generatingcompound; introducing the acidizing fluid into a subterranean formationcomprising one or more subterranean zones; and monitoring a dispositionof the acidizing fluid within the subterranean formation using one ormore integrated computational elements in optical communication with thesubterranean formation.

Acid-generating compounds include substances that degrade (e.g., withina subterranean formation) to produce at least one acid. Suitableacid-generating compounds may include, for example, esters, orthoestersand degradable polymers such as polylactic acid and polyglycolic acid.

In addition to at least one acid or acid-generating compound, acidizingfluids suitable for use in the present embodiments may optionallycontain other components in addition to the at least one acid. Two ofthe more notable components are chelating agents and/or corrosioninhibitors, for example. Chelating agents can slow or prevent theprecipitation of formation solids that are liberated upon reaction withan acid. Corrosion inhibitors can slow or prevent the degradation ofmetal tools used during the performance of an acidizing operation. Othercomponents that can optionally be present in the acidizing fluids of thepresent embodiments include for example, a surfactant, a gelling agent,a salt, a scale inhibitor, a polymer, an anti-sludging agent, adiverting agent, a foaming agent, a buffer, a clay control agent, aconsolidating agent, a breaker, a fluid loss control additive, arelative permeability modifier, a tracer, a probe, nanoparticles, aweighting agent, a rheology control agent, a viscosity modifier, and anycombination thereof. Any of these additional components can also bemonitored using an integrated computational element according to themethods described herein.

In some embodiments, a diverting fluid may be introduced into thesubterranean formation in conjunction with performing an acidizingoperation with an acidizing fluid. In some embodiments, the divertingfluid may be introduced to the subterranean formation before introducingthe acidizing fluid. In some or other embodiments, the diverting fluidmay be introduced to the subterranean formation concurrently withintroducing the acidizing fluid. In still other embodiments, theacidizing fluid itself may comprise a diverting agent, and the acidizingfluid may be self-diverting.

In some embodiments, acidizing fluids being monitored using one or moreintegrated computational elements may comprise at least one acid. Invarious embodiments, the at least one acid may comprise a mineral acidsuch as hydrofluoric acid or hydrochloric acid, for example. In some orother embodiments, the at least one acid may comprise an organic acidsuch as formic acid, acetic acid, glycolic acid, or lactic acid forexample. As one of ordinary skill in the art will recognize, the type ofsubterranean formation being treated with the acidizing fluid maydictate the choice of acid used. When treating a carbonate formation,for example, it may be more desirable to use hydrochloric acid, formicacid, or acetic acid. These acids may be ineffective for acidizing asiliceous formation such as, for example, a sandstone formation. Whenacidizing a sandstone formation, treatment with hydrofluoric acid may bemore desirable.

In some embodiments, the subterranean formation being treated with anacidizing fluid and monitored by the methods described herein maycomprise a carbonate formation. In some embodiments, the subterraneanformation being treated with an acidizing fluid and monitored by themethods described herein may be penetrated by a wellbore comprising asubstantially horizontal section. When acidizing a wellbore having asubstantially horizontal section, the present methods may beparticularly advantageous, since over-stimulation of the heel of thewellbore is a commonly encountered problem in the art. By applying thepresent methods, one can determine if an acidizing fluid has beendisposed in a desired location and if a desired effect has beenachieved.

In some embodiments, the subterranean formation being treated with theacidizing fluid and monitored by the methods described herein maycomprise a siliceous formation, such as a sandstone formation, forexample. As discussed above, siliceous formations may be effectivelyacidized with acidizing fluids containing hydrofluoric acid or ahydrofluoric acid-generating compound. Acidizing operations in siliceousformations may be monitored, for example, by detecting the presence ofhydrofluoric acid in the subterranean formation or a reaction productformed from the hydrofluoric acid and a component of the subterraneanformation. Specifically, the reaction product being monitored maycomprise dissolved silicates and/or aluminosilicates leeched from thematrix of the subterranean formation. In addition to monitoring theprogression of hydrofluoric acid, a hydrofluoric acid-generatingcompound, or a reaction product formed therefrom in a subterraneanformation, the production of various insoluble materials from thereaction product may also be monitored using the integratedcomputational elements. As one of ordinary skill in the art willrecognize, silicates, fluorosilicates, and fluoroaluminates may reactunder certain conditions (e.g., in the presence of alkali metals) toform highly insoluble precipitates that may damage the subterraneanformation being treated. The precipitates may be very difficult toremediate. Accordingly, the ability to detect the production of thesesubstances when acidizing a siliceous formation may represent an addedbenefit of monitoring fluid progression using one or more integratedcomputational elements. A more detailed discussion of the problemsassociated with acidizing siliceous formations may be found in commonlyowned U.S. patent application Ser. No. 12/917,167, filed on Nov. 1,2010, and Ser. No. 13/051,827, filed on Mar. 18, 2011, each of which isincorporated herein by reference in its entirety.

In some, monitoring a disposition of the acidizing fluid in thesubterranean formation may comprise monitoring a progression of theacidizing fluid in the subterranean formation. In some embodiments, aflow rate of the acidizing fluid within the subterranean formation maybe determined by monitoring its progression therein. In some or otherembodiments, monitoring a disposition of the acidizing fluid in thesubterranean formation may comprise monitoring a placement of theacidizing fluid in the subterranean formation. In some embodiments, themethods may further comprise determining an amount of penetration of theacidizing fluid into a subterranean zone using one or more integratedcomputational elements. Determining an amount of penetration of theacidizing fluid into a subterranean zone may comprise, for example,monitoring a constituent concentration and/or characteristic of theacidizing fluid as it changes over time. For example, a decrease in aconstituent concentration may be indicative of its penetration into asubterranean zone. In a similar manner to that described above,monitoring a disposition of the acidizing fluid within a subterraneanformation using one or more integrated computational elements maycomprise, for example, measuring pH, detecting the at least one acid ora reaction product formed therefrom, or any combination thereof. Changesin the composition or characteristics of the acidizing fluid may beindicative of its reaction with the surface of the subterraneanformation, thereby resulting in dissolution of the formation matrix. Forexample, when acidizing a carbonate formation, dissolution of theformation matrix may result in the desirable creation of wormholeswithin the formation face that result in an increase in itspermeability. Detection of carbon dioxide or dissolved ions from theformation matrix (e.g., Ca²⁺) may be used to monitor disposition of theacidizing fluid in various embodiments.

Although the presence of a reaction product formed between the acidizingfluid and the formation matrix may be indicative of the acidizingfluid's penetration into the subterranean formation, in some cases, thesubterranean formation's permeability may still not be increased to adesired degree. Specifically, in some embodiments, bulk erosion of thesurface of the subterranean formation may occur rather than the desiredwormhole formation. Simply monitoring the subterranean formation for thecreation of a reaction product or consumption of the acidizing fluid maybe insufficient in some cases to determine whether wormhole formation orbulk erosion has occurred, since the acidizing fluid is consumed and thesame reaction product formed in either case. To distinguish betweenwormhole formation and bulk erosion, in some embodiments, it may bedesirable to monitor for other components of the formation matrix thatmay be liberated during acidizing. For example, during wormholeformation, it is expected that primarily the acid-soluble components ofthe formation matrix will be released. In contrast, during bulk erosion,secondary components of the subterranean formation that are notnecessarily acid soluble may be released from the formation matrix intothe acidizing fluid. Detection of an excessive amount of these secondarycomponents using one or more integrated computational elements mayindicate that the acidizing operation needs to be altered in somemanner. For example, in some embodiments, if secondary componentanalysis indicates bulk erosion rather than wormhole formation, the flowrate of the acidizing fluid may be altered or its concentration may bechanged.

In still other embodiments, monitoring a disposition of the acidizingfluid within the subterranean formation may further comprise monitoringa surface within the subterranean formation. For example, in someembodiments, bulk erosion of the surface of the subterranean formationmay be detected using an integrated computational element that ispositioned to monitor the formation face itself and is configured todetect a constituent therein. Specifically, a change in output of anintegrated computational element monitoring the formation face may beindicative of bulk erosion. For example, a distance between theformation face and the integrated computational element may be increasedby bulk erosion, such that less electromagnetic radiation that hasoptically interacted with the formation face is received by theintegrated computational element. With wormhole formation, in contrast,it is believed that the distance between the formation face and theintegrated computational element will not change appreciably, such thatthe amount of received electromagnetic radiation remains roughly thesame. In some embodiments, the surface being monitored within theformation may comprise the well string, for example. For example, in anacidizing operation, pitting of the well string by the acidizing fluidmay be monitored using an integrated computational element monitoringthe well string's surface.

In some embodiments, the techniques described herein may also beapplicable in injection operations, such as those used in enhanced oilrecovery. In injection operations, a fluid may be injected into a firstwellbore for the purposes of pressurizing the subterranean formation, soas to stimulate one or more neighboring wellbores. The injection fluidmay flow from the injection wellbore to the neighboring wellbores, andfluid pressure exerted by the injection fluid may drive a formationfluid toward the neighboring wellbores, thereby allowing the formationfluid to be produced. The injection fluid may also chemically change aflow pathway between the injection wellbore and the neighboringwellbores so as to reduce resistance of the formation fluid flowingtoward the neighboring wellbores. For example, in some embodiments, asurfactant within the injection fluid may reduce the interfacial tensionbetween the subterranean formation and the formation fluid, therebyallowing the formation fluid to flow more easily to the one or moreneighboring wellbores.

When conducting injection operations, dyes or like tracers are oftenincluded within the injection fluid in order to provide a marker formonitoring the progression of the injection fluid from a first locationto a second location. In the case of injection operations, progressionof the dyes or like tracers from the injection wellbore to theneighboring wellbore(s) may be indicative of the passage of theinjection fluid therebetween. Passage of the injection fluid from theinjection wellbore to the production wellbore may be indicative that theinjection operation has functioned as intended and predictive of thesuccess of the injection operation. Current methods of analyzing for thedyes or like tracers may not be possible in real-time or near real-time,particularly while the injection fluid is downhole, which may limitone's ability to proactively control an injection operation.

In some embodiments, tracers and/or probes can be deployed in the fluidsused in the present methods. As used herein, the term “tracer” refers toa substance that is used in a fluid to assist in the monitoring of thefluid in a subterranean formation or in a fluid being produced from asubterranean formation. Illustrative tracers can include, for example,fluorescent dyes, radionuclides, and like substances that can bedetected in exceedingly small quantities. A tracer typically does notconvey information regarding the environment to which it has beenexposed, unlike a probe. As used herein, the term “probe” refers to asubstance that is used in a fluid to interrogate and deliver informationregarding the environment to which it has been exposed. Upon monitoringthe probe, physical and chemical information regarding a subterraneanformation can be obtained.

In some embodiments, the present methods can comprise monitoring atracer or a probe in a fluid using an integrated computational element.In some embodiments, the tracer or probe can be monitored in a fluidbeing produced from a subterranean formation. In other embodiments, thetracer or probe can be monitored within the subterranean formation. Insome embodiments, tracers or probes in a fluid can be monitored using anintegrated computational element in order to determine a flow pathwayfor the fluid in the subterranean formation. In some embodiments,monitoring of tracers or probes can be used to determine the influenceof diverting agents on the flow pathway.

In some embodiments, methods described herein may comprise: providing aninjection wellbore penetrating a subterranean formation, the injectionwellbore being in fluid communication with one or more neighboringwellbores; introducing an injection fluid to the injection wellbore; andmonitoring a progression of the injection fluid within the injectionwellbore or in the one or more neighboring wellbores using one or moreintegrated computational elements in optical communication with theinjection wellbore or the one or more neighboring wellbores. In someembodiments, introducing the injection fluid to the injection wellboremay comprise pressurizing the injection wellbore with the injectionfluid. In some embodiments, pressurizing the injection wellbore maystimulate the one or more neighboring wellbores so as to produce aformation fluid, such as oil.

In some embodiments, monitoring a progression of the injection fluid inthe injection wellbore or in the one or more neighboring wellbores maytake place in real-time or near real-time.

In some embodiments, the injection fluid may comprise aspectroscopically active substance. In some embodiments, the injectionfluid may comprise a spectroscopically active substance within a fluidphase, which may comprise an aqueous fluid in some embodiments. In someembodiments, the spectroscopically active substance of the injectionfluid may comprise a dye or like tracer that is conventionally used ininjection operations. For example, in some embodiments, thespectroscopically active substance may comprise a fluorescent molecule.

In some embodiments, monitoring a progression of the injection fluidwithin the subterranean formation may comprise detecting aspectroscopically active substance within the injection wellbore or inthe one or more neighboring wellbores. Detecting the disappearance ofthe spectroscopically active substance within the injection wellbore mayprovide evidence of its progression therefrom. Detecting the appearanceof the spectroscopically active substance within the one or moreneighboring wellbores may provide direct evidence of its progressionthereto.

In some embodiments, the injection fluid may lack a dye or like tracer.In such embodiments, monitoring a progression of the injection fluid maytake place by analyzing for a component of the injection fluid or acharacteristic thereof using one or more integrated computationalelements in optical communication with the injection wellbore or the oneor more neighboring wellbores.

It is to be recognized that the fluids described herein may furthercomprise various additional components other than those expresslydescribed. Illustrative substances that can be present in any of thefluids described herein may include, for example, acids, acid-generatingcompounds, bases, base-generating compounds, surfactants, scaleinhibitors, corrosion inhibitors, gelling agents, crosslinking agents,anti-sludging agents, foaming agents, defoaming agents, antifoam agents,emulsifying agents, de-emulsifying agents, iron control agents,proppants or other particulates, gravel, particulate diverters, salts,fluid loss control additives, gases, catalysts, clay control agents,chelating agents, corrosion inhibitors, dispersants, flocculants,scavengers (e.g., H₂S scavengers, CO₂ scavengers or O₂ scavengers),lubricants, breakers, delayed release breakers, friction reducers,bridging agents, viscosifiers, weighting agents, solubilizers, rheologycontrol agents, viscosity modifiers, pH control agents (e.g., buffers),hydrate inhibitors, relative permeability modifiers, diverting agents,consolidating agents, fibrous materials, bactericides, tracers, probes,nanoparticles, and the like. Combinations of these substances can beused as well. Any of these additional substances may be detected andanalyzed using one or more integrated computational elements in order tomonitor the disposition of the fluid within the subterranean formation.

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered,combined, or modified and all such variations are considered within thescope and spirit of the present invention. The invention illustrativelydisclosed herein suitably may be practiced in the absence of any elementthat is not specifically disclosed herein and/or any optional elementdisclosed herein. While compositions and methods are described in termsof “comprising,” “containing,” or “including” various components orsteps, the compositions and methods can also “consist essentially of” or“consist of” the various components and steps. All numbers and rangesdisclosed above may vary by some amount. Whenever a numerical range witha lower limit and an upper limit is disclosed, any number and anyincluded range falling within the range is specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues. Also, the terms in the claims have their plain, ordinary meaningunless otherwise explicitly and clearly defined by the patentee.Moreover, the indefinite articles “a” or “an,” as used in the claims,are defined herein to mean one or more than one of the element that itintroduces. If there is any conflict in the usages of a word or term inthis specification and one or more patent or other documents that may beincorporated herein by reference, the definitions that are consistentwith this specification should be adopted.

1. A method comprising: introducing a first fluid into a subterraneanformation; and monitoring a disposition of the first fluid within thesubterranean formation using one or more integrated computationalelements in optical communication with the subterranean formation. 2.The method of claim 1, wherein the subterranean formation is penetratedby a wellbore, and the one or more integrated computational elements arelocated within the wellbore.
 3. The method of claim 2, wherein aplurality of integrated computational elements are sited at multiplelocations within the wellbore.
 4. The method of claim 3, whereinmonitoring a disposition of the first fluid comprises determining aprogression of the first fluid within the wellbore using the pluralityof integrated computational elements.
 5. The method of claim 1, furthercomprising: after or while monitoring a disposition of the first fluidwithin the subterranean formation, analyzing for a constituent or acharacteristic of the first fluid within the subterranean formationusing one or more integrated computational elements.
 6. The method ofclaim 1, wherein monitoring a disposition of the first fluid within thesubterranean formation comprises detecting a constituent or acharacteristic of the first fluid, a reaction product formed from aconstituent of the first fluid, a substance formed in the absence of thefirst fluid, or any combination thereof.
 7. The method of claim 1,wherein the first fluid comprises at least one treatment fluid selectedfrom the group consisting of an acidizing fluid, a fracturing fluid, adiverting fluid, a scale inhibitor fluid, a corrosion inhibitor fluid, afriction reducing fluid, an injection fluid, and any combinationthereof.
 8. The method of claim 1, further comprising: after monitoringa disposition of the first fluid within the subterranean formation,introducing a second fluid to the subterranean formation, the secondfluid being the same as or different than the first fluid.
 9. The methodof claim 1, further comprising: before introducing the first fluid tothe subterranean formation, performing a diverting operation in thesubterranean formation.
 10. The method of claim 1, wherein monitoring adisposition of the first fluid within the subterranean formationcomprises monitoring a placement of the first fluid within asubterranean zone.
 11. The method of claim 1, wherein monitoring adisposition of the first fluid within the subterranean formation takesplace in real-time or near real-time.
 12. The method of claim 1, furthercomprising: altering the first fluid after monitoring its dispositionwithin the subterranean formation.
 13. A method comprising: providing aninjection wellbore penetrating a subterranean formation, the injectionwellbore being in fluid communication with one or more neighboringwellbores; introducing an injection fluid to the injection wellbore; andmonitoring a progression of the injection fluid within the injectionwellbore or in the one or more neighboring wellbores using one or moreintegrated computational elements in optical communication with theinjection wellbore or the one or more neighboring wellbores.
 14. Themethod of claim 13, wherein introducing an injection fluid to theinjection wellbore pressurizes the injection wellbore and stimulates theone or more neighboring wellbores.
 15. The method of claim 13, whereinthe injection fluid comprises an aqueous fluid.
 16. The method of claim13, wherein the injection fluid comprises a spectroscopically activesubstance within a fluid phase.
 17. The method of claim 16, whereinmonitoring a progression of the injection fluid comprises detecting thespectroscopically active substance within the injection wellbore or inthe one or more neighboring wellbores.
 18. A method comprising:providing a diverting fluid comprising a diverting agent; introducingthe diverting fluid into a subterranean formation comprising one or moresubterranean zones; after or while introducing the diverting fluid,introducing a treatment fluid to the subterranean formation; andmonitoring a disposition of the treatment fluid within the subterraneanformation using one or more integrated computational elements in opticalcommunication with the subterranean formation.
 19. The method of claim18, wherein monitoring a disposition of the treatment fluid within thesubterranean formation comprises monitoring a placement of the treatmentfluid within a subterranean zone.
 20. The method of claim 18, furthercomprising: monitoring a disposition of the diverting fluid within thesubterranean formation using one or more integrated computationalelements in optical communication with the subterranean formation. 21.The method of claim 18 wherein the treatment fluid comprises at leastone treatment fluid selected from the group consisting of an acidizingfluid, a fracturing fluid, a scale inhibitor fluid, a corrosioninhibitor fluid, a friction reducing fluid, an injection fluid, and anycombination thereof.
 22. The method of claim 18, further comprising:after or while monitoring the disposition of the treatment fluid withinthe subterranean formation, detecting a constituent or a characteristicof the treatment fluid within the subterranean formation using one ormore integrated computational elements.
 23. The method of claim 18,wherein at least one integrated computational element is sitedsubstantially adjacent to each subterranean zone.
 24. The method ofclaim 18, further comprising: altering the treatment fluid aftermonitoring its disposition within the subterranean formation.